Study On Robust Scheduling Of Flexible Job Shop Based On Process Relationship Network Under Machine Failure

With the increasingly fierce market competition,the era of continuous production in large quantities is gradually being replaced by a variety of small batch production methods that can adapt to the dynamic changes in the market.The uncertainty of workshop production elements in the workshop manufacturing system also increases,resulting in frequent disturbance of the production plan in the execution process,resulting in deviation of the actual production process from the plan,and the stability of the workshop production process decreases.The machine is the main resource of the workshop.If the disturbance caused by the machine failure to the workshop scheduling is reduced,the stability of the workshop can be guaranteed.Therefore,how to develop a robust scheduling scheme with anti-interference capability has become a hot topic in production scheduling research.In this paper,a process relationship network is established according to the correlation among workshop elements.Secondly,in the case of machine failure,the analysis process is affected by the forward associated process,and the robust scheduling method of FJSP is proposed.Finally,the propagation process of process disturbance in the network and its influence on the scheduling performance,namely the stability,are analyzed,and the process influence is evaluated,so as to analyze the scheduling robustness through the process proportion.The main research contents of this paper are as follows:(1)According to the characteristics of the production process in the flexible job shop,the correlation between the basic production factors is analyzed,including the workshop elements of machine,workpiece,preventive maintenance,etc.On the basis of the disjunctive diagram,the flexible working shop process relationship network is established according to the characteristics of the problem and the examples,which provides the basis for the follow-up research.(2)Aiming at the effects of workshop machine problem of scheduling schemes,key resources to machine shop,the shop scheduling,the preventive maintenance and buffer time three organic combination,can be mapped to the process in the network,and analysis process by itself and its influences to the associated process delay before,the size of the insert size to determine the buffer time.An adaptive preventive maintenance and buffer time insertion strategy is proposed,a FJS robust scheduling integrated optimization model is established,and an effective algorithm is designed to solve the problem.Simulation results show that this method can effectively improve the robustness of scheduling solutions.(3)Considering that different process faults have different impacts on scheduling schemes,the proportional effect of buffer time insertion on the robustness of scheduling solutions is further analyzed,and the process influence propagation network and the process influence evaluation model are established.The buffer time is inserted after the process with large process influence according to the process proportion.The simulation results show that the buffer time is allocated according to the process influence,which reduces the buffer time waste,and the scheduling stability is significantly improved by sacrificing less scheduling performance.